Initial vegetative growth and graft region anatomy of yellow passion fruit on Passiflora spp. rootstocks

•Cleft grafting led to similar plant growth of yellow passion fruit on five Passiflora spp.•P. gibertii outperformed other wild species for potential use as rootstock.•Structural disorganization in the graft connection was observed on P. alata and P. nitida..•Phenolic compounds were observed in the graft union suggesting partial incompatibility.•The graft connection may be enhanced on hybrid rootstocks of P. edulis with wild species.

The grafting of the yellow passion fruit onto wild species tolerant to Fusarium spp. is an alternative practice for this disease control. High vigor and tissue compatibility between the scion and the rootstock are critical for the production of grafted passiflora nursery trees. The initial plant growth and histological aspects of the graft union were evaluated on two Passiflora edulis genotypes grafted onto P. edulis, P. gibertii, P. alata, P. nitida and backcross BC1 [(P. edulis x P. cincinnata) x P. edulis]. Plant survival was high (∼90%) up to 60 days after grafting, regardless of the scion neither the rootstock, and in relation to the respective non-grafted seedlings. P. gibertii resulted in higher plant emergence after P. edulis, higher growth of seedling rootstocks and induced higher length of the P. edulis graft. The complete union between tissues was observed in P. edulis grafted onto P. edulis, P. gibertii and BC1 60 days after grafting. On the other hand, a discrete structural disorganization with incomplete adhesion and phenolic compounds accumulation was verified in the connection of P. edulis onto P. nitida and P. alata, suggesting partial graft incompatibility, even though grafted plants growth was restored. All evaluated genotypes have potential of use as rootstock of the yellow passion fruit. The graft connection may be enhanced on hybrid rootstocks of P. edulis with wild species.